Differences in vascular risk factors between etiological subtypes of ischemic stroke: importance of population-based studies

The rs2200733 variant on chromosome 4q25 is a risk factor for cardioembolic stroke related to atrial fibrillation in Polish patients

BACKGROUND AND PURPOSE

A few single nucleotide polymorphisms (SNPs) on chromosome 4q25, associated with atrial fibrillation (AF), are risk factors for ischaemic stroke. We studied the significance of the SNP rs2200733 on chromosome 4q25 in different types of cardioembolic (CE) stroke.

MATERIAL AND METHODS

We genotyped 428 controls and 301 CE stroke patients, among whom 197 (65.4%) presented with high risk sources of embolism (CE stroke related to AF) and 104 with medium risk sources (CE stroke unrelated to AF). The SNP rs2200733 was analysed using real-time polymorphism chain reaction.

RESULTS

Both univariate and multivariate regression analyses showed that the studied variant affected risk of all CE strokes or CE strokes related to AF in recessive and additive mo-dels. The two types of CE stroke differed significantly in demographics and distribution of vascular risk factors.

CONCLUSIONS

The SNP rs2200733 on chromosome 4q25 is a risk factor for CE stroke related to AF only.

Stroke in diabetic patients

Stroke is the leading cause of disability and the second most frequent cause of death worldwide. On the one hand, diabetic patients have a 1.5 to 3-times higher risk of stroke, especially cerebral infarction, than non-diabetic subjects. This excess risk, which is particularly pronounced in younger individuals and women, can be reduced by effective therapeutic strategies aimed at improving glycaemic control and the management of co-morbid conditions such as hypertension and dyslipidaemia. On the other hand, the prevalence of diabetes in stroke patients is between 10 and 20%, and has been increasing over the last 20 years, probably in response to rising rates of overweight and obesity in the general population and other factors such as a sedentary lifestyle. Even though diabetes has long been considered a specific risk factor of lacunar stroke, recent epidemiological studies have demonstrated that this risk factor was in fact not associated with any ischemic stroke subtype. Finally, it has been suggested that diabetic stroke patients have poorer motor and functional outcomes, and are at a higher risk of dementia, recurrent stroke and death.

Paroxysmal atrial fibrillation in cryptogenic stroke

INTRODUCTION

Paroxysmal atrial fibrillation (PAF) is perhaps the most underdiagnosed mechanism of apparent cryptogenic stroke (CS). Various studies have shown that increasing the duration of monitoring can increase the diagnosis of PAF in CS.

METHODS

We compared demographic and risk factors for ischemic stroke across different TOAST (Trial of ORG 10172 in Acute Stroke Treatment) stroke subtypes to look for clinical differences between other subtypes and CS and subsequently performed periodic Holter monitoring and imaging studies in apparent CS patients.

RESULTS

Of the 298 patients with ischemic stroke, 17% had CS. Periodic holter monitoring enabled diagnosis of PAF in 29% of patients. Five of 51 patients with CS had recurrent ischemic stroke and all 5 were demonstrated as PAF on repeated Holter monitoring.

CONCLUSIONS

Long-term periodic rhythm monitoring in patients with apparent CS showed PAF in a significant percentage of CS patients, which altered subsequent treatment.

A critical review of aspirin in the secondary prevention of noncardioembolic ischaemic stroke

Both secondary prevention (such as lifestyle modifications, pharmacotherapy or surgery) and an understanding of the influence of risk factors (including the different aetiologic mechanisms of cerebral ischaemia) play a pivotal role in reducing the burden of recurrent stroke. Regarding the types of preventative treatments available, variations exist across all clinical studies, including differences in target populations (including the type of cerebral ischaemia), risk factors, length of follow-up, drop-out rates and outcomes, which makes translating the results of clinical trials to individual patients difficult. However, with such limitations in mind, this critical albeit nonsystematic review, which compared aspirin with other antiplatelets and in combination with other drugs, showed that the benefit from aspirin treatment is consistently shown in ischaemic stroke, while harms are limited. Furthermore, no definite superiority is apparent across different antiplatelet therapies. Dual antiplatelet regimens may expose to a slight but measurable higher risk of haemorrhagic complications, perhaps in selective groups of patients (i.e. those with severe small-vessel disease or in selective racial groups). Based on our analysis, the indication of aspirin as the first-line choice, also recommended by several acknowledged international or national guidelines, may be confirmed. However, the complex nature of patients at risk of recurrent ischaemic stroke necessitates a comprehensive approach, which should be driven by the primary care physician, whose role is central to successful actions for secondary stroke prevention.

Evaluation of platelet activation, coagulation, and fibrinolytic activation in patients with symptomatic lacunar stroke

BACKGROUND

It is unclear whether hemostasis plays a role in the pathogenesis of ischemic stroke subtypes.

OBJECTIVE

We aimed to investigate the possible relationship between different hemostatic markers and lacunar stroke.

RESULTS

The study consisted of 30 patients with symptomatic lacunar stroke and 30 healthy age-matched healthy individuals. We analyzed the values of "Mean Platelet Volume," D-dimer, "soluble p-selectin," "Plasminogen Activator Inhibitor Type-1" (PAI-1), "Thrombin-Activatable Fibrinolysis Inhibitor" (TAFI), and "Platelet Factor 4" (PF4) in patients with lacunar infarct and compared these values to those of control individuals. There were significant differences for D-dimer, mean platelet volume, thrombin-activatable fibrinolysis inhibitor, and platelet factor 4 values in symptomatic lacunar stroke group compared with the control group (P < 0.01).

CONCLUSIONS

Different hemostatic factors may play a role in the pathogenesis of lacunar stroke. Evaluating the role of hemostatic factors on different types of strokes may help us identify new therapeutic strategies and different prognostic stratifications for ischemic stroke.

The Prevalence of Peripheral Arteriopathy is Higher in Ischaemic Stroke as Compared with Transient Ischaemic Attack and Intracerebral Haemorrhage

Background:

There is little data on the association of peripheral arterial disease and stroke. We aimed to assess the prevalence of peripheral arterial disease in acute stroke and to identify the predisposing factors for peripheral arterial disease in a stroke cohort.

Methods:

We enrolled all consecutive patients who were admitted to our stroke- and neurocritical care units with the diagnosis of a transient ischaemic attack, ischaemic or haemorrhagic stroke over a period of 5 months. As controls, we analysed 50 nonvascular neurological patients who were matched to age. Upon admission, assessment of the ankle brachial index was performed in all patients. The only exclusion criteria was decompensated congestive heart failure.

Results:

Altogether, we compared 374 stroke patients (95 transient ischaemic attack, 231 ischaemic, and 48 haemorrhagic strokes) and 50 nonstroke controls. The prevalence of peripheral arterial disease in the control group was 14%. There was a trend towards a higher prevalence of peripheral arterial disease in stroke patients (χ2-test: P = 0.051; prevalence peripheral arterial disease in transient ischaemic attack: 16.8%, ischaemic stroke: 32%, and haemorrhagic stroke: 20.8%). A higher proportion of ischaemic stroke patients were peripheral arterial disease-positive, compared with transient ischaemic attack patients ( P = 0.005) and controls ( P = 0.011), respectively. Multivariate regression analyses identified the parameters age, arterial hypertension, current or former smokers and a history of cardiovascular events to be predisposing factors of peripheral arterial disease.

Conclusion:

This study represents the first systematic investigation of the prevalence of peripheral arterial disease in stroke. By now, it is clear that: • peripheral arterial disease is more commonly found in stroke than in nonstroke patients • ischaemic stroke patients show the highest prevalence of peripheral arterial disease, and • peripheral arterial disease in stroke is related to common vascular risk factors.

Differing risk factor profiles of ischemic stroke subtypes: evidence for a distinct lacunar arteriopathy?

BACKGROUND AND PURPOSE

Differences in risk factor profiles between lacunar and other ischemic stroke subtypes may provide evidence for a distinct lacunar arteriopathy, but existing studies have limitations. We overcame these by pooling individual data on 2875 patients with first-ever ischemic stroke from 5 collaborating prospective stroke registers that used similar, unbiased methods to define risk factors and classify stroke subtypes.

METHODS

We compared risk factors between lacunar and nonlacunar ischemic strokes, altering the comparison groups in sensitivity analyses, and incorporated these data into a meta-analysis of published studies.

RESULTS

Unadjusted and adjusted analyses gave similar results. We found a lower prevalence of cardioembolic source (adjusted odds ratio, 0.33; 95% CI, 0.24 to 0.46), ipsilateral carotid stenosis (odds ratio, 0.21; 95% CI, 0.14 to 0.30), and ischemic heart disease (odds ratio, 0.75; 95% CI, 0.58 to 0.97) in lacunar compared with nonlacunar patients but no difference for hypertension, diabetes, or any other risk factor studied. Results were robust to sensitivity analyses and largely confirmed in our meta-analysis.

CONCLUSIONS

Hypertension and diabetes appear equally common in lacunar and nonlacunar ischemic stroke, but lacunar stroke is less likely to be caused by embolism from the heart or proximal arteries, and the lower prevalence of ischemic heart disease in lacunar stroke provides additional support for a nonatherosclerotic arteriopathy causing many lacunar ischemic strokes. Our findings have implications for how clinicians classify ischemic stroke subtypes and highlight the need for additional research into the specific causes of and treatments for lacunar stroke.

LDL and HDL subclasses in acute ischemic stroke: prediction of risk and short-term mortality

OBJECTIVE

Small, dense low-density lipoprotein (sdLDL) and small-sized high-density lipoprotein (HDL) particles are established risk factors for ischemic heart disease. However, their clinical significance for acute ischemic stroke (AIS) is uncertain. This study evaluates associations of LDL and HDL particle sizes and subclasses with AIS risk and short-term mortality after AIS.

METHODS

Two hundred AIS patients hospitalised for first-in-a-lifetime stroke and 162 apparently healthy controls were included in the study. LDL and HDL particles were separated by gradient gel electrophoresis and serum lipid parameters were measured by standard laboratory methods. Baseline characteristics of LDL and HDL particles were evaluated for the prediction of AIS and short-term mortality after AIS.

RESULTS

AIS patients had significantly more LDL III and IVb, but less LDL I and II particles. They also had significantly smaller HDL size, more HDL 3a, 3b and 3c and less HDL 2b subclasses. The relative content of both sdLDL and small-sized HDL particles was significantly increased in patients (P<0.001 and P<0.001, respectively). In addition, sdLDL was significantly higher in AIS fatalities (n=25) compared with survivors (n=175, P<0.05). Increased sdLDL was a significant predictor of AIS (OR=4.31; P<0.001) and in-hospital mortality after AIS (OR=5.50; P<0.05). The observed relationships persisted after adjustment for conventional risk factors.

CONCLUSIONS

AIS is associated with adverse distributions of LDL and HDL subclasses. In addition, short-term mortality after AIS is associated with increased sdLDL particles. Our results indicate that sdLDL is an independent predictor of both AIS onset and consecutive short-term mortality.

Changes in risk factors and preventive treatments by stroke subtypes over 20 years: a population-based study

In order to evaluate progress in preventive therapeutic strategies, and to identify potential targets for improvement, it is essential to assess changes in the risk factors and preventive treatment of stroke over time. All of the strokes occurring within the population of Dijon, France (150,000 inhabitants), were prospectively ascertained from 1985 to 2004. Changes in stroke risk factors and preventive medications were analyzed by stroke subtypes. We recorded 725 lacunar infarcts (LI), 497 cardioembolic (CE) strokes, 2054 ischemic stroke from atheroma of large arteries or from other and undetermined causes (OIS), and 341 primary cerebral haemorrhages (PCH). Over the 20years, the prevalence of hypercholesterolemia increased whatever the stroke subtype (p<0.01) whereas that of diabetes only rose in LI and OIS stroke. The proportion of stroke patients on antiplatelet agents increased overall (p<0.01) and the proportion of patients on anticoagulants rose in CE stroke (p=0.01) and PCH (p<0.01). The proportion of patients on antihypertensive treatment only increased in CE stroke (p=0.01). The risk factor profile and the preventive treatments in stroke patients showed divergent variations over the 20years, according to the stroke subtype considered. These modifications certainly reflect changes in the therapeutic strategies for the preventive management of the population at risk.

Does glycated hemoglobin have clinical significance in ischemic stroke patients?

OBJECTIVES

It has been suggested that patients with an elevated hemoglobin A1c (HbA1c) level have an increased risk of cardiovascular disease regardless of the presence of diabetes. However, an association between HbA1c and stroke has not yet been determined. In this study, our purpose was to examine whether HbA1c was independently associated with various types of cerebral vascular lesions in stroke patients.

METHODS

A consecutive series of acute ischemic stroke patients were included for this analysis from October, 2002, to March, 2006. HbA1c was examined on admission, and MR imaging was performed for analysis of large artery diseases (LADs) and small artery diseases (SADs). Symptomatic or asymptomatic LAD was diagnosed by MR angiography, and SAD was classified as leukoaraiosis, microbleeds, or old lacunar infarctions.

RESULTS

A total of 639 stroke patients were analyzed (diabetics, n=247; non-diabetics, n=392). There was no relationship between the level of HbA1c and any type of cerebrovascular lesion in the non-diabetic patients. In contrast, HbA1c showed a significant negative association with symptomatic LAD and leukoaraiosis in the diabetic patients using univariate analysis (p=0.01 and p<0.05, respectively). These associations did not remain significant, however, after adjustment for age and hypertension. This was, in part, because the HbA1c level in our diabetic population decreased gradually with age (p=0.03).

CONCLUSIONS

Our results indicate that HbA1c is not associated with risk for various types of cerebrovascular lesions in ischemic stroke patients. The negative association between age and HbA1c in diabetic patients should be further investigated.

Blood pressure-lowering treatment for primary and secondary prevention of different types of stroke

High blood pressure is the most important modifiable risk factor for stroke and accumulating evidence indicates that blood pressure levels are likely to be associated with all stroke subtypes. There is also evidence from randomized trials suggesting that blood pressure-lowering treatment provides protection against every stroke subtype in both primary and secondary prevention settings. Blood pressure lowering is likely to be one of the most effective and generalizable strategies across a variety of stroke subtypes.

Association between cholesterols, homocysteine and silent brain infarcts

BACKGROUND

The aim of this study was to assess the relationship between total plasma homocysteine, cholesterol levels, vitamin B(12), folate, thyroid hormones, urea, ferritin, uric acid, C-reactive protein, cardiovascular risk factors and silent brain infarct (SBI) in patients without any neurological disorder. Whether the factors of interest were associated with SBI is investigated.

METHODS

One hundred and forty-two subjects with a mean age of 52.1 +/- 13.1 years (21-87 years) without any history of stroke, transient ischaemic attack and neurological abnormality were enrolled in this cross-sectional study. The subjects underwent brain magnetic resonance imaging and blood chemistry determinations. Student's t-test was used to compare differences in means of laboratory results between the groups with and without SBI. The chi(2)-test was used for categorized variables. Multiple logistic regression analysis was used to determine the independent predictors of SBI.

RESULTS

The group comprised 56 men and 86 women. SBI were found in 40 patients (28%). The low-density lipoprotein levels were significantly higher in the infarct group (P = 0.019), homocysteine concentrations were significantly higher in the men-infarct group (P = 0,029) and total cholesterol levels were significantly higher in the women-infarct group than the women non-infarct group (P = 0.006).

CONCLUSION

Serum low-density lipoprotein, total cholesterol and homocysteine levels were associated with SBI.

A-G-4G haplotype of PAI-1 gene polymorphisms -844 G/A, HindIII G/C, and -675 4G/5G is associated with increased risk of ischemic stroke caused by small vessel disease

BACKGROUND

Plasminogen activator inhibitor type 1 (PAI-1) is the major inhibitor of fibrinolysis. It was reported that PAI-1 gene polymorphisms affected PAI-1 level and might therefore influence the risk of vascular diseases, including stroke. We studied the association of three common polymorphisms in PAI-1 gene (-844 G/A, -675 4G/5G, and HindIII G/C) with the odds of different causes of ischemic stroke.

METHODS

We studied 390 patients with ischemic stroke due to large vessel disease (n = 117), small vessel disease (n = 121), and cardioembolism (n = 152) as well as 291 controls. The etiology of ischemic stroke was established using TOAST criteria. PAI-1 polymorphisms were genotyped with restriction fragment length polymorphism and single strand conformation polymorphism method.

RESULTS

A-G-4G haplotype of PAI-1 gene was found more frequently in stroke patients with small vessel disease than in control subjects (44.9% vs 35.7%; P = 0.02). No association was found between investigated genotype or allele frequencies and distinct causes of ischemic stroke.

CONCLUSIONS

Our results demonstrate that A-G-4G PAI-1 gene haplotype is associated with increased risk of small vessel disease stroke, but this study does not support an association of -844 G/A, -675 4G/5G, and HindIII G/C PAI-1 gene polymorphisms with particular etiology of ischemic stroke.

Risk Factors and Stroke Subtypes: Results of Five Consecutive Years of the Perugia Stroke Registry

To understand the etiopathogenetic mechanisms of stroke and to target prevention, we need to know how risk factors differ among etiological subtypes. Our aims were to determine the different profile of risk factors for ischemic and hemorrhagic stroke subtypes in our cohort from the Perugia Hospital-Based Stroke Registry. We analyzed the characteristics and the different risk factors of 2,395 first-ever consecutive stroke patients admitted to the Perugia Hospitals in the period between January 1, 1998 and December 31, 2002. The prevalence of cerebrovascular risk factors in each stroke subtype was analyzed independently and compared with other subtypes of stroke pooled together by means of univariate analysis and logistic regression models. Hypertension occurred in 61% of patients; familial history of stroke in 41.6%; vascular disease in 27.2%; embolic heart disease in 22.3%; cigarette smoking in 21.6%. Different potentially modifiable risk factors profiles were identified for each ischemic subtype of stroke, while in hemorrhagic lobar stroke subtypes, only male gender was an independent risk factor.

[Cryptogenic cerebral infarction: from classification to concept]

Since the foundations laid by Sacco and Mohr in 1989, from the Stroke data bank, cryptogenic infarctions have had a predominant place among the causes of ischemic strokes. In that study, they accounted for approximately 40% of the stroke causes. Cryptogenic infarctions are infarctions without a defined cause, despite a complete work-up; they differ from infarctions of undetermined causes, which may involve overlapping causes or an incomplete investigation. The size of this group will probably shrink as knowledge advances. Patent foramen ovale (PFO), with or without a septal aneurysm, is more frequent in patients with a cryptogenic infarction. Transesophageal echocardiography is the reference examination for screening for these abnormalities. A meta-analysis of several case-control studies showed a significant association between PFO and stroke in subjects younger than 55 years. For now, these septal abnormalities constitute a risk factor but not a cause. Complex aortic atheroma affecting area upstream of the left subclavian artery may be a source of cerebral embolisms in some conditions. The prevalence of this disease increases with age. It is identified most frequently in patients older than 60 years with a cryptogenic infarction. The thickness of the atheromatous plaque determines whether it is a risk factor or a cause. Recent stroke classifications do not consider carotid atheromatous lesions less than 50% to be a source of ischemic stroke. Nonetheless some studies identify moderate stenosis of the carotid artery more frequently in infarctions of unknown causes than in other categories. The increased risk of cerebral infarction when parents and homozygous twins have a history of stroke suggests that there may be genetic causes that have not yet been detected. An unknown genetic cause would thus be included in the infarctions of unknown causes. A recent study tested for Fabry disease in young patients with a cryptogenic infarction: 4.9% of the men and 2.4% of the women had a functional mutation of the alpha-galactosidase gene. These findings must be confirmed. Some studies suggest an association between cryptogenic infarction and hereditary thrombophilias. Nonetheless the risk attributable to these thrombophilic disorders is slight and the discovery may be only a coincidence. The work described above shows the importance of stratification in the identification of stroke causes: age older or younger than 55/60 years, type of interatrial abnormality (PFO and aneurysms of the interatrial septum), type of atheroma of the aortic arch (more or less than 4mm). They also show the difficulty involved in attributing cause to an identified abnormality: is carotid stenosis of less than 50% a marker of atherosclerosis or also a cause of stroke? To continue improving our understanding of the mechanisms of strokes, new investigational techniques are under evaluation. They include magnetic resonance imaging (MRI), computed tomographic angiography (CT), positron emission tomography (PET) of carotid plaque and of the aortic arch, transcranial Doppler, cardiac recording by telemetry, and even new biological assays.

Sex differences in incidence, mortality, and survival in individuals with stroke in Scotland, 1986 to 2005

BACKGROUND AND PURPOSE

The aim of this study was to examine the effect of sex across different age groups and over time for stroke incidence, 30-day case-fatality, and mortality.

METHODS

All first hospitalizations for stroke in Scotland (1986 to 2005) were identified using linked morbidity and mortality data. Age-specific rate ratios (RRs) for comparing women with men for both incidence and mortality were modeled with adjustment for study year and socioeconomic deprivation. Logistic regression was used to model 30-day case-fatality.

RESULTS

Women had a lower incidence of first hospitalization than men and size of effect varied with age (55 to 64 years, RR=0.65, 95% CI 0.63 to 0.66; >or=85 years, RR=0.94, 95% CI 0.91 to 0.96). Women aged 55 to 84 years had lower mortality than men and again size of effect varied with age (65 to 74 years, RR=0.79, 95% CI 0.76 to 0.81); 75 to 84 years, RR=0.94, 95% CI 0.92 to 0.95). Conversely, women aged >or=85 years had 15% higher stroke mortality than men (RR=1.15, 95% CI 1.12 to 1.18). Adjusted risk of death within 30 days was significantly higher in women than men, and this difference increased over the 20-year period in all age groups (adjusted OR in 55 to 64 year olds 1.23, 95% CI 1.14 to 1.33 in 1986 and 1.51, 95% CI 1.39 to 1.63 in 2005).

CONCLUSIONS

We observed lower rates of incidence and mortality in younger women than men. However, higher numbers of older women in the population mean that the absolute burden of stroke is greater in women. Short-term case-fatality is greater in women of all ages and, worryingly, these differences have increased from 1986 to 2005.

[Smoking and stroke]

Up to one quarter of all strokes are directly attributable to cigarette smoking, that percentage can get up to 50% for young adults admitted for an cryptogenic ischemic stroke. Cigarette smoking increases the relative risk of ischemic stroke about two-fold, three-fold for subarachnoid haemorrhage. Current smoking is not clearly identified as a risk factor for intra-cerebral haemorrhage. The risk is consistent for all subtypes of stroke according aetiology and is strongest for ischemic stroke caused by arterial atherothromboembolism. The risk is dependent upon the amount of cigarettes smoked and passive smoking is a substantial risk of stroke. The relative risk is maximal in middle age, declining with advancing years. The toxicity is higher among female smokers, especially when they have several risk factors such as oral contraceptiveS and migraine with aura. Whereas it is well known that the effectiveness of cigarette withdrawal reduces the risk of new vascular event, two thirds of young patients continue to smoke.

Differentiating ischemic stroke subtypes: risk factors and secondary prevention

Ischemic strokes account for 87% of all strokes in the US. Patients who suffer an initial ischemic stroke or transient ischemic attack are at risk for recurrent strokes, as well as ischemic events in the coronary and peripheral vasculatures. Lifestyle modifications and pharmacological and surgical interventions are effective in reducing the risk of recurrent events in all stroke patients, and evidence-based guidelines for secondary stroke prevention are available. However, increasing evidence indicates that risk factors may be differentially associated with specific ischemic stroke subtypes. In the future, exploiting these differential associations may facilitate secondary stroke prevention and, therefore, improve patient outcomes.

Usefulness of haptoglobin and serum amyloid A proteins as biomarkers for atherothrombotic ischemic stroke diagnosis confirmation

OBJECTIVE

To identify protein biomarkers in order to classify ischemic stroke subtypes using proteomic analysis and immunoenzymatic tools for clinical validation.

METHODS AND RESULTS

We performed a proteomic analysis in serum samples of 24 patients with ischemic stroke (12 atherothrombotic patients and 12 cardioembolic patients). In this study, based on two-dimensional electrophoresis and mass spectrometry we found four spots whose expression intensity was at least four times stronger in atherothrombotic patients than in cardioembolic patients. These spots were identified as haptoglobin related protein, serum amyloid A (two spots) and haptoglobin alpha chain. We validated the possible value of haptoglobin and serum amyloid A in a larger series of patients (n=262) with ischemic stroke using ELISA techniques. Haptoglobin levels >1040microg/mL identified atherothrombotic patients with 95% sensitivity and 88% specificity whereas serum amyloid A levels >160microg/mL identified atherothrombotic patients with 91% sensitivity and 83% specificity.

CONCLUSIONS

Haptoglobin and serum amyloid A are useful biomarkers for atherothrombotic ischemic stroke diagnosis confirmation.

Association between Ngb polymorphisms and ischemic stroke in the Southern Chinese Han population

Background

Neuroglobin (Ngb), one of novel members of the globin superfamily, is expressed predominantly in brain neurons, and appears to modulate hypoxic-ischemic insults. The mechanisms underlying Ngb-mediated neuronal protection are still unclear. For it is one of the candidate protective factors for ischemic stroke, we conducted a case-control study to clarify the association of Ngb polymorphisms with ischemic stroke in the Southern Chinese Han population.

Methods

355 cases and 158 controls were recruited. With brain imaging, cases were subdivided into large-artery atherosclerosis (LVD) and small-vessel occlusion (SVD) stroke. PCR amplified all the four exons of Ngb and flanking intron sequence for each exon. Genotyping for Ngb was achieved by direct sequencing and mismatched PCR-RFLP. Polymorphisms were studied both individually and as haplotypes in each group and subgroup which subdivided according to gender or age.

Results

Two intronic polymorphisms 89+104 c>t and 322-110 (6a)>5a were identified. The allele frequency of 89+104 t was decreased in stroke cases. The protective effect seems to be more pronounced in subgroups of female patients and age > 60 years. Also, we have confirmed decreased LDL-C level and reduced hypertension and hypercholesterolemia in 89+104 t allele carriers. In contrast, the 322-110 (6a)>5a genotype distribution was similar between cases and controls. However, the haplotype 89+104 c>t/322-110 (6a)>5a was related with LVD and SVD stroke. The haplotype c-5a was more frequent in both LVD and SVD groups while t-6a was more frequent in controls.

Conclusion

Ngb polymorphism 89+104 t had protective effects on LVD and SVD in the Southern Chinese Han population. A "hitchhiking" effect was observed for the 89+104 t/322-110 (6a) genotype combination especially for LVD.

Age-distinct predictors of symptomatic cervicocephalic atherosclerosis

BACKGROUND

Little is known about whether vascular risk factors predispose to atherosclerotic stroke depending on age. We evaluated predictors of large vessel atherosclerotic stroke (LVAS) stratified by age in two geographically and racially distinct study populations.

METHODS

Data collected over a 4-year period in prospectively maintained registries on 3,053 subjects with ischemic cerebrovascular events were analyzed: 1,982 patients from a hospital in South Korea and 1,071 patients admitted to a hospital in Los Angeles, Calif., USA. Independent vascular risk factor associations with LVAS mechanism were evaluated in three groups stratified by age (years) at symptom onset: young (75 years).

RESULTS

Altogether at both study sites, 972 (31.8%) patients had LVAS mechanism, of whom 391 (40.2%) were female. Risk factor profiles were not significantly different between LVAS versus other stroke mechanisms. Among young patients, after adjusting for covariates, current smoking was the only predictor of atherosclerotic stroke at both Korean (OR 2.04; 95% CI: 1.13-3.69) and Californian sites (OR 4.78, 95% CI 1.54-14.89), while the metabolic syndrome was the only predictor of atherosclerotic stroke among the older patients (OR 1.58, 95% CI 1.17-2.12 for Korean; OR 1.75, 95% CI 1.07-2.84 for Californian), but not in the young or oldest groups.

CONCLUSIONS

Across race and region, the estimated impact of vascular risk factors for LVAS varies by age, and this is most prominently seen among persons of less than 76 years of age. Some risk factors have an early effect (smoking) and others an effect that plays out over time.

Central periodic breathing during sleep in 74 patients with acute ischemic stroke - neurogenic and cardiogenic factors

OBJECTIVES

The aims of our study were 1) to better characterize central periodic breathing during sleep (CPBS) and its clinical relevance in acute stroke, 2) to better define the role of brain damage in its pathogenesis.

METHODS

We included 74 consecutive patients admitted within 96 hours after stroke onset. Stroke severity at admission, stroke outcome at discharge and stroke topography were assessed. ECG and transesophageal echocardiography were performed. Nocturnal breathing was assessed with an ambulatory device the first night after admission. CPBS severity was represented as absolute time and percentage of recording time.

RESULTS

Age was 63 +/- 13 (25-82), 49 (66 %) were male. Thirty (41 %) patients showed CPBS during >or= 10 % and 7 (9 %) during >or= 50 % of recording time. CPBS severity was associated with age (p = 0.017), stroke severity (p = 0.008), ECG abnormalities (p = 0.005) and lower left ventricular ejection fraction (p < 0.0001). CPBS severity was higher in patients with extensive hemispheric strokes (n = 6, p < 0.0001), and lower in patients with partial strokes involving the left insula (n = 5, p < 0.0001) and the mesencephalon (n = 5, p = 0.002).

CONCLUSIONS

CPBS is frequent in acute ischemic stroke and is associated with older age, stroke severity/extension, and lower left ventricular function. The lower occurrence of CPBS in left insular and mesencephalic stroke suggests a major role of distinct brain areas in the modulation of respiratory phenomena accompanying acute stroke.

Recorded Categories of Non-Principal Diagnoses in Victorian Public Hospital Transient Ischaemic Attack and Stroke Admissions

Information about the number and types of non-principal diagnoses (NPDs) would make an important contribution to prediction of outcome and hence patient management. The study reported here is based on analysis of three fiscal years of the Victorian public hospital transient ischaemic attack (TIA) and stroke admissions. The incidence of NPDs and co-occurrence of NPD-associated prefix categories (that identify the onset or relevance of each condition to the episode) are described in each of the broad stroke subtypes. The distributions of length of stay and in-hospital deaths in the cohorts without and with NPDs and in the various prefix categories are determined. The study also compares the age and gender distribution in the various subpopulations of interest. The importance of collecting complete and accurate data on nature of NPDs and its potential in describing the complexity of presentation are discussed.

ApoB/ApoA-I ratio in young patients with ischemic cerebral stroke or peripheral arterial disease

Although smoking and hypertension are classic risk factors for atherothrombotic diseases, the relationship of dyslipidemia and vascular diseases, other than myocardial infarction, is less clearly established, especially in young subjects. In the current study, a detailed analysis of the lipid and apolipoprotein profiles was conducted in young patients of ischemic cerebral stroke (IS) and peripheral arterial disease (PAD). Plasma levels of C-reactive protein (hs-CRP), total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), triglycerides (TG), and apolipoproteins A-I (ApoA-I) and apolipoproteins B (ApoB), which include the ApoB/ApoA-I ratio, were analyzed in a group of 81 patients who presented with IS (n = 46) or PAD (n = 35) as well as in 167 control subjects. Significant differences were observed for hs-CRP, TC, HDLc, LDLc, TG, ApoA-I, and ApoB levels, as well as for the ApoB/ApoA-I ratio, between the control and the IS or PAD groups. However, after adjustment for sex, age, smoking, hypertension, hs-CRP, and dyslipidemia (LDLc, TC, HDLc, TG, ApoA, ApoB, and ApoB/ApoA-I ratio), hs-CRP, ApoB, and the ApoB/ApoA-I ratio were independently associated with increased risks of IS or PAD. Increased ApoB/ApoA-I ratio and hs-CRP levels are independently associated with occurrence of IS and PAD in young patients and are significant markers of alterations on lipid and apolipoproteic profiles and inflammatory responses, respectively, in these patients.

Characteristics of TIA and its management in a tertiary care hospital in Pakistan

BACKGROUND

Transient ischemic attack (TIA) is described as a brief episode of neurological dysfunction caused by focal brain ischemia, with clinical symptoms typically lasting less than an hour, and without evidence of acute infarction. Recent studies depict TIA as a particularly unstable condition. Risk of stroke is greater than 10% in the first 90 days after an index TIA. The presentation, prognosis and intervention for TIA have not been reported in South-Asians in a developing country.

METHOD

A retrospective chart review was done for 158 patients who were admitted with the diagnosis of TIA, as defined by ICD 9 code 435, from January 2003 to December 2005 at the Aga Khan University Hospital, Karachi, Pakistan. The data was entered and analyzed in SPSS version 14.0.

FINDINGS

Among 158 patients, 57.6% were male and 41.1% were female. The common presenting symptoms were motor symptoms (51.3%), speech impairment (43%), sensory impairment (34.8%) and loss of balance/vertigo (29.1%). The median delay in presenting to the hospital was 4 hours. Those with motor symptoms were found to present earlier. The study showed that only 60.8% of all the patients presenting with TIA received any immediate treatment out of which 44.7% received aspirin. Neuroimaging was used in 91.1% of the patients. Of all the TIA patients 9.1% converted to stroke with 50% doing so within the first 24 hours.

CONCLUSION

The natural history of TIA from this developing nation is comparable to international descriptions. A large percentage of patients are still not receiving any immediate treatment as recommended in available guidelines, even in a tertiary care hospital.

Trends in Incidence, Risk Factors, and Survival in Symptomatic Lacunar Stroke in Dijon, France, From 1989 to 2006

Background and Purpose— Lacunar infarcts are usually regarded as benign stroke, but population-based studies are required to assess the exact place of this stroke subtype in cerebrovascular pathology.

Methods— We evaluated trends in incidence rates, risk factor profiles, and survival rates in symptomatic lacunar stroke from a prospective population-based registry from 1989 to 2006.

Results— We recorded 2536 ischemic strokes. Among these, 715 (28%) were lacunar infarcts (354 men and 361 women). From 1989 to 2006, we observed a significant rise in the incidence of lacunar stroke in the 2 sexes considered together (relative risk, 1.02; 95% CI, 1.005 to 1.035; P =0.007), whereas the variation was not significant in either men or women when considered separately. Incidence rates significantly increased in young patients under 65 years old (relative risk, 1.049; 95% CI, 1.0175 to 1.0817; P =0.002). Concerning the distribution of cerebrovascular risk factors, lacunar stroke differed from nonlacunar stroke only with regard to the lower prevalence of a history of atrial fibrillation in the former ( P <0.001). For lacunar infarcts, survival rates were 96% at 1 month (95% CI, 0.94 to 0.97), 86% at 1 year (95% CI, 0.83 to 0.89), and 78% at 2 years (95% CI, 0.75 to 0.81) and were significantly higher than those for nonlacunar stroke (hazard ratio, 2.05; 95% CI, 1.70 to 2.47; P <0.001).

Conclusion— Our results suggest a significant increase in the incidence rates of lacunar stroke with a relatively good short-term prognosis in terms of survival. The association among hypertension, diabetes mellitus, and lacunar stroke was no stronger than the association between these 2 risk factors and nonlacunar stroke.

Diabetes increases large artery diseases, but not small artery diseases in the brain

BACKGROUND

It is established that diabetes causes various systemic micro- and macro-vascular complications. Little has been, however, studied on the differential effects of diabetes on the large artery diseases (LAD) or small artery disease (SAD) in the brain. The purpose of this study was to examine an association of diabetes on the incidence of underlying LAD versus SAD in ischemic stroke patients.

METHODS

We prospectively collected 523 acute ischemic stroke patients without cardioembolic causes or other determined causes of stroke. Using brain MRI, the cerebral LAD (extracranial and intracranial arterial stenosis of 50 % or more) and the cerebral SAD (old lacunar infarction, microbleeds and leukoaraiosis) findings were assessed. Information regarding vascular risk factor was also collected.

RESULTS

Among the patients (male, n = 342; diabetes, n = 200), diabetes was not associated with the presence of LADs or SADs in female subjects, but strongly with the presence of intracranial LAD in male subjects (p < 0.01). The association remained significant (OR 2.09, 95 %CI 1.25-3.51) after adjusting for major confounders. A similar association was also found in intracranial LAD and insulin resistance. There was, however, no significant association of diabetes with SAD in male nor in female patients.

CONCLUSIONS

Our results showed that diabetes is associated with the frequency of intracranial LAD, especially in males. Out study may be regarded as evidence of differential biological effects of diabetes on cerebral vasculature.

Action on vascular risk factors: importance of blood pressure and lipid lowering in stroke secondary prevention

INTRODUCTION

Secondary stroke prevention comprises a broad spectrum of therapeutic actions that includes the appropriate management of risk factors and the action on blood pressure and serum lipids that are of great importance to decrease stroke recurrences.

METHODS

We conducted a review of the published studies analyzing the relevance of the treatment of blood pressure and serum lipids, with special attention to recent findings of clinical trials and current guidelines on stroke secondary prevention.

RESULTS

The relationship between blood pressure and stroke has been widely demonstrated; however, the role of serum lipids has been discussed for a long time. Recent results from epidemiological studies and clinical trials have demonstrated its role as modifiable risk factor for stroke. Blood pressure and lipid lowering are associated with significant reductions in recurrent strokes as well as in other vascular events in transient ischemic attack (TIA) or stroke patients. The PROGRESS and MOSES trials suggest that diuretics, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers could confer additional benefits in stroke patients, and the SPARCL study did so for statins. These drugs are not only efficacious in the reduction of stroke recurrences, but also in other cardiovascular events.

CONCLUSIONS

Blood pressure and serum lipids are two important and modifiable vascular risk factors that should be taken into consideration when planning secondary stroke prevention measures. This approach should include hypotensive drugs (mainly the combination of diuretics and ACE inhibitors) with the objective to maintain normal blood pressure, avoiding levels >130/80 mm Hg in all stroke patients, and statins (atorvastatin 80 mg) in patients with noncardioembolic TIA or stroke.

Association of apolipoprotein E polymorphism with ischemic stroke subtypes in Taiwan

The aim of this study was to clarify whether the apolipoprotein E gene (APOE) is related to ischemic stroke subtypes in Taiwan's Chinese population. Using the classification of Cerebrovascular Diseases III, 143 patients with lacunar infarction, 114 patients with atherothrombotic infarction, and 112 healthy controls were enrolled. APOE genotype was determined using polymerase chain reaction. Regarding the distribution of APOE genotypes, the frequency of epsilon3/epsilon4 genotypes in lacunar patients was significantly different from that in control subjects, by logistic regression, using epsilon3/epsilon3 as a reference group. There was no significant difference between atherothrombotic patients and the control group in the distribution of APOE genotypes or alleles. The present finding suggests that there is a probable association between epsilon3/epsilon4 genotype and lacunar infarcts, but not atherothrombotic infarcts. This indicates that genetic factors may play a role, at least partially, in lacunar infarction in Taiwan's Chinese population.

The combination of homozygous MTHFR 677T and angiotensin II type-1 receptor 1166C variants confers the risk of small-vessel-associated ischemic stroke

Previous studies have suggested that both angiotensin II type-1 receptor (AT1R) 1166C and methylenetetrahydrofolate reductase (MTHFR) 677T variants can have disadvantageous effects on the small-vessel circulation under certain conditions. The purpose of this study was to analyze the possible consequences of the simultaneous distribution of these two genetic variants in different types of ischemic stroke. The genetic and clinical data on 357 ischemic stroke patients and 263 control subjects were analyzed by using univariate and logistic statistical approaches. Neither the MTHFR 677T nor the AT1R 1166C genetic variant alone conferred the risk of any subtype of ischemic stroke. The combination of the homozygous MTHFR 677TT genotype and at least one AT1R 1166C allele occurred more frequently in the ischemic stroke patients (8.68%) than in the controls (4.56%, p < 0.05). Specific subclassification of the patients revealed an accumulation of this combination in small-vessel-associated ischemic stroke (12.2%, p < 0.01); multivariate logistic regression analysis of the data confirmed this association, with an odds ratio of 2.66 (95% confidence interval, 1.28-7.89; p < 0.05). These findings suggest that the combination of these two genetic factors can contribute to the development of small-vessel cerebral infarcts. Although the exact mechanism of action is not known, addition of the unfavourable effects on the endothelial function can be presumed.

Higher total serum cholesterol levels are associated with less severe strokes and lower all-cause mortality: ten-year follow-up of ischemic strokes in the Copenhagen Stroke Study

BACKGROUND AND PURPOSE

Evidence of a causal relation between serum cholesterol and stroke is inconsistent. We investigated the relation between total serum cholesterol and both stroke severity and poststroke mortality to test the hypothesis that hypercholesterolemia is primarily associated with minor stroke.

METHODS

In the study, 652 unselected patients with ischemic stroke arrived at the hospital within 24 hours of stroke onset. A measure of total serum cholesterol was obtained in 513 (79%) within the 24-hour time window. Stroke severity was measured with the Scandinavian Stroke Scale (0=worst, 58=best); a full cardiovascular risk profile was established for all. Death within 10 years after stroke onset was obtained from the Danish Registry of Persons.

RESULTS

Mean+/-SD age of the 513 patients was 75+/-10 years, 54% were women, and the mean+/-SD Scandinavian Stroke Scale score was 39+/-17. Serum cholesterol was inversely and almost linearly related to stroke severity: an increase of 1 mmol/L in total serum cholesterol resulted in an increase in the Scandinavian Stroke Scale score of 1.32 (95% CI, 0.28 to 2.36, P=0.013), meaning that higher cholesterol levels are associated with less severe strokes. A survival analysis revealed an inverse linear relation between serum cholesterol and mortality, meaning that an increase of 1 mmol/L in cholesterol results in a hazard ratio of 0.89 (95% CI, 0.82 to 0.97, P=0.01).

CONCLUSIONS

The results of our study support the hypothesis that a higher cholesterol level favors development of minor strokes. Because of selection, therefore, major strokes are more often seen in patients with lower cholesterol levels. Poststroke mortality, therefore, is inversely related to cholesterol.

Secular trends in the cardiovascular risk profile and mortality of stroke admissions in an inner city, multiethnic population in the United Kingdom (1997–2005)

Our objective was to study ethnic differences in the cardiovascular risk profile and mortality of stroke admissions to an inner city teaching hospital serving a multiethnic population in Birmingham, UK, over a 9-year period (1997-2005). Hospital case notes and registry data of 3083 patients admitted with a first onset stroke were reviewed. Secular trends in the prevalence of risk factors (hypertension, diabetes, hyperlipidaemia, atrial fibrillation and myocardial infarction), hospital admission rates and 30-day mortality among Afro-Caribbean, European Caucasian and South Asian ethnic groups were analysed. Between 1997 and 2005, there were 3083 first onset strokes, of whom 47.6% (1595) were men, 9.3% Afro-Caribbean, 57.8% European Caucasian and 15.1% South Asian. There was a significant trend towards a reduction in non-haemorrhagic stroke admissions over the study period (P<0.001), with no ethnic variation (P=0.07). Increases in hypertension and hyperlipidaemia were observed (P<0.001), whereas myocardial infarction showed a decline (P<0.001). Compared to other ethnic groups, South Asian patients were younger on admission (P<0.001), had more hyperlipidaemia (P<0.05) and poorer survival at 30 days (P=002). We conclude that cardiovascular risk profiles among patients admitted with non-haemorrhagic stroke have changed over the last decade. In particular, hyperlipidaemia has increased, especially among South Asians. The reduced decline in stroke admissions and 30-day survival of stroke in South Asians in recent years warrants further investigation and highlights the importance of a targeted health-care approach in the migrant ethnic minorities.

Risk factor profile of cerebral small vessel disease and its subtypes

BACKGROUND

The mechanisms of cerebral small vessel disease (SVD) are unclear. Both atherosclerosis and a non-atherosclerotic diffuse arteriopathy have been reported pathologically. Two pathological and radiological subtypes have been suggested: localised atherosclerotic disease in larger perforating arteries causing larger lacunar infarcts without leukoaraiosis, and diffuse disease in smaller arterioles causing multiple smaller lacunar infarcts with leukoaraiosis. If atherosclerosis were important in SVD as a whole or in one particular subtype, one would expect the risk factor profile to be similar to that of cerebral large vessel disease (LVD).

METHODS

Risk factor profiles were compared in Caucasian stroke patients with SVD (n = 414), LVD (n = 471) and 734 stroke-free Caucasian population controls. Patients with SVD were subdivided according to the presence or absence of confluent leukoaraiosis, into isolated lacunar infarction (ILI) and ischaemic leukoaraiosis (ILA).

RESULTS

Hypertension was commoner in SVD than LVD (odds ratio (OR) 3.43 (2.32 to 5.07); p<0.001) whereas hypercholesterolaemia (OR 0.34 (0.24 to 0.48); p<0.001), smoking (OR 0.63 (0.44 to 0.91); p = 0.012), myocardial infarction (OR 0.35 (0.20 to 0.59); p<0.001) and peripheral vascular disease (OR 0.32 (0.20 to 0.50); p<0.001) were commoner in LVD. Among SVD patients, age (OR 1.11 (1.09 to 1.14); p<0.001) and hypertension (OR 3.32 (1.56 to 7.07); p = 0.002) were associated with ILA and hypercholesterolaemia (OR 0.45 (0.28 to 0.74); p = 0.002), diabetes (OR 0.42 (0.21 to 0.84); p = 0.014) and myocardial infarction (OR 0.18 (0.06 to 0.52); p = 0.001) with ILI.

CONCLUSION

SVD has a different risk factor profile from the typical atherosclerotic profile found in LVD, with hypertension being important. There are differences in the risk factor profile between the SVD subtypes; the association of ILI with hypercholesterolaemia, diabetes and myocardial infarction may be consistent with a more atherosclerotic aetiology.

Short-term effects of ozone air pollution on ischaemic stroke occurrence: a case-crossover analysis from a 10-year population-based study in Dijon, France

OBJECTIVE

To evaluate the association between air pollutants and the occurrence of acute stroke from 10-year population-based study.

METHODS

The daily stroke count was obtained from Dijon Stroke Register between March 1994 and December 2004. The register recorded all first-ever strokes among residents of Dijon (150,000 inhabitants) in France, using standard diagnostic criteria. Pollutant concentrations (SO2, CO, NO2, O3 and PM10) were measured hourly. A bi-directional case-crossover design was used to examine the association between air pollutant and stroke onset. The conditional logistic regression model included the meteorological parameters (temperature, relative humidity), influenza epidemics and holidays.

RESULTS

The authors collected 493 large artery infarcts, 397 small artery infarcts, 530 cardio-embolic infarcts, 67 undeterminate infarcts, 371 transient ischaemic attacks and 220 haemorrhagic strokes. For single-pollutant model and for a 10 mg/m(3) increase of O3 exposure, a positive association was observed only in men, over 40 years of age, between ischaemic stroke occurrence and O3 levels with 1-day lag, (OR 1.133, 95% CI 1.052 to 1.220) and 0-day lag (OR 1.058, 95% CI 0.987 to 1.134). No significant associations were found for haemorrhagic stroke. In two-pollutant models, the effects of O3 remained significant after each of the other pollutants were included in the model, in particular with PM10. A significant association was observed for ischaemic strokes of large arteries (p = 0.02) and for transient ischaemic attacks (p = 0.01). Moreover, the authors found an exposure-response relations between O3 exposure and ischaemic stroke (test for trend, p = 0.01). An increase in association in men with several cardiovascular risk factors (smoker, dyslipidemia and hypertension) was also observed.

CONCLUSION

These observational data argue for an association between ischaemic stroke occurrence and O3 pollution levels; these results still need to be confirmed by other studies.

Stroke epidemiology, prevention, and management strategies at a regional level: Latin America and the Caribbean

Stroke is a major health problem in Latin American and Caribbean countries. In this paper, we review the epidemiology, aetiology, and management of stroke in the region based on a systematic search of articles published in Spanish, Portuguese, and English. Stroke mortality is higher than in developed countries but rates are declining. Population-based studies show variations in incidence of strokes: lower rates of ischaemic stroke and similar rates of intracranial haemorrhages, compared with other regions. A significant proportion of strokes in these populations can be attributed to a few preventable risk factors. Some countries have published national clinical guidelines, although much needs to be done in the organisation of care and rehabilitation. Even though the burden of stroke is high, there is a paucity of information for implementing evidence-based management. The Global Stroke Initiative, the WHO STEPS Stroke surveillance, and WHO-PREMISE projects provide opportunities for surveillance at institutional and community levels.

Variations in the use of diagnostic procedures after acute stroke in Europe: results from the BIOMED II study of stroke care

Valid classification of stroke is essential to initiate effective acute management and early secondary prevention strategies. To accurately evaluate stroke subtype a number of diagnostic procedures have to be performed. This study sought to investigate variations in use of diagnostic procedures across selected European hospitals. First-ever stroke patients were sampled over a 1-year period through 11 hospital-based registers across 10 European countries. We defined a diagnostic standard for valid aetiological classification of ischemic stroke including brain imaging, vascular imaging and echocardiography. The impact of socio-demographic, clinical and structural characteristics on performance of the diagnostic standard was assessed using multivariate logistic regression analyses. A total of 1721 patients were included in the study. 83.1% received brain imaging, ranging from 32.8% to 100%. The diagnostic standard was performed in 40.4% of stroke patients, ranging from 0% to 77.2%. Patients with increasing age (P < 0.001) and with more severe strokes (P = 0.001) were less probably to receive the diagnostic standard. Patients treated in stroke units and neurological departments were more frequently investigated with the diagnostic standard (P < 0.001). Less than half of hospitalized stroke patients across Europe underwent diagnostic procedures to allow for aetiological classification of stroke, which may hamper the initiation of effective early management and secondary prevention.

Lack of aggregation of ischemic stroke subtypes within affected sibling pairs

OBJECTIVE

To establish whether subtypes of ischemic stroke aggregate within ischemic stroke-affected sibling pairs more than expected by chance alone.

METHODS

This retrospective family study was based on a pooled analysis of two cohorts of male and female adult sibling pairs with symptomatic ischemic stroke. One hospital-based cohort of 404 individuals (first proband seen August 30, 1999) was recruited from the United States and Canada, and another population-based cohort of 198 individuals (first proband seen April 17, 1997) was recruited from Umeå, Sweden. Subtype diagnoses were based on Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria.

RESULTS

Agreement for subtype diagnoses within families was poor (mean +/- asymptotic SE kappa = 0.17 +/- 0.04). Occurrence of one ischemic stroke subtype in a proband was not associated with a greater likelihood of that subtype being the qualifying stroke subtype in the sibling. Comparable levels of agreement were seen when restricting the analysis to same-sex sibling pairs (kappa = 0.22 +/- 0.05) to sibling pairs in which the proband's stroke occurred before the age of 65 years (kappa = 0.16 +/- 0.05) or to pairs in which the proband's stroke occurred at or after the age of 65 years (kappa = 0.19 +/- 0.05).

CONCLUSIONS

The subtype of ischemic stroke in a proband was a poor determinant of the subtype of ischemic stroke in the respective sibling. This suggests that many genetic risk factors for ischemic stroke may not be specific for one subtype.

Incidence, case-fatality rate, and prognosis of ischaemic stroke subtypes in a predominantly Hispanic-Mestizo population in Iquique, Chile (PISCIS project): a community-based incidence study

BACKGROUND

Incidence of ischaemic stroke subtypes, classified by cause, seems to vary between communities. We aimed to prospectively ascertain the incidence of first-ever ischaemic stroke in a predominantly Hispanic-Mestizo population in the northern desertic region of Chile.

METHODS

Between July, 2000, and June, 2002, all patients with possible stroke or transient ischaemic attacks were identified from multiple overlapping sources and were rapidly assessed by two field neurologists. All identified patients were diagnosed by at least two stroke neurologists according to Trial of Org 10172 in Acute Stroke Treatment (TOAST) definitions and were followed up at 6 months. Annual incidence rates were age adjusted to WHO, European, and US populations by the direct method to allow comparisons.

FINDINGS

A total of 239 ischaemic strokes were identified, of which 185 (77%) were first-ever cases. 151 (82%) patients were hospitalised, of whom only 70 (38%) were assessed within 6 h of symptom onset. The mean age of patients was 66.4 years (SD 14.9) and 56% were men. The crude annual incidence rates (per 100 000) according to stroke subtype were: cardioembolic, 9.3; large-artery disease, 2.0; small-vessel disease, 15.8; other determined cause, 0.2; and undetermined cause, 17.4. Hypertension was the most common cardiovascular risk factor in all subtypes and atrial fibrillation was the most common cause of cardioembolic stroke. Case fatality at 30 days was highest in cardioembolic strokes (28%) and lowest in small-vessel disease (0%). Dependency or death at 6 months was also highest in cardioembolic strokes (62%) and lowest in small-vessel disease (21%).

INTERPRETATION

Incidence and prognosis of small vessel and cardioembolic infarction was similar to that in other populations and incidence of large-artery atherothrombotic infarction was lower than in most previous reports. Hypertension and atrial fibrillation were the most common risk factor and cause, respectively, of ischemic stroke in this population. These findings should help the national stroke programme in the prevention of cardioembolic stroke, increase access to specialists and acute brain imaging and vascular studies, and improve stroke care.